NORMAL AND PATHOLOGICAL GROWTH 155 



remedied by later growth of the gland, but fortunately, arti- 

 ficial medication can be continued indefinitely. 



Experimental cretinism results when the thyroid gland is 

 surgically removed in young animals. Figure 79 shows a cretin 

 sheep produced by Dr. Sutherland Simpson 7 by removing the 

 thyroid gland from two-months-old lamb. In comparison with 

 the adult sheep these cretins were 

 "squat and stunted in growth, with 

 misshapen rickety limbs, and the 

 general appearance was listless and 

 stupid." The wool was coarse and 

 rough and the body temperature was 

 lower than that of the normal sheep. 

 All these factors compare very well 

 with observations on the human 

 cretin. 



Hypothyroidism of later life of 

 the human produces a picture of the 

 body also very characteristic. There 

 are many such unfortunates, espe- 

 cially among women in whom the 

 condition appears at the age of forty- 

 five or fifty, or even later. These ab- 

 normal types are called myxedemas. 

 They have full round faces, thick, 

 heavy but firm skin, heavy, clubbed 



hands and fingers, thick cheeks, lips, nose, and eyelids, they are 

 nervous but inactive, lethargic, listless, and dispirited. The opti- 

 mistic and aggressive reactions of the normal human are pro- 

 duced by the simple method of feeding the proper amount of 

 artificially prepared desiccated thyroid gland containing the 

 hormone. Fortunately, thyroid gland itself can be taken as food 

 without the necessity of extracting the pure hormone, and it 

 seems to produce in the body the good effects that come from 

 normal production of the thyroid. 



Figure 80. A case due to hypo- 

 thyroidism or myxedema occur- 

 ring in adult life. The club-shaped 

 fingers, heavy features, and the 

 listlessness of the eyes and facial 

 expression are characteristic. 

 From Tigerstedt's Textbook of 

 Physiology by R. Tigerstedt and 

 John R. Murlin. By permission 

 of D. Appleton and Company, 

 New York. 



